diff --git a/CMLibGlobalVariables.cmake b/CMLibGlobalVariables.cmake
index 2b0153b..72ef17d 100644
--- a/CMLibGlobalVariables.cmake
+++ b/CMLibGlobalVariables.cmake
@@ -11,7 +11,7 @@ foreach(_m ${CMAKE_MODULE_PATH})
   endif()
 endforeach()
 
-if(CMLIB_MODULE_DIR)
+if(IS_DIRECTORY "${CMLIB_MODULE_DIR}")
   if(NOT DEFINED CMLIB_THIRDPARTY_DIR)
     set(CMLIB_THIRDPARTY_DIR "${CMLIB_MODULE_DIR}/thirdparty")
     list(APPEND CMAKE_MODULE_PATH ${CMLIB_THIRDPARTY_DIR})
diff --git a/CMLibSanitizers.cmake b/CMLibSanitizers.cmake
index 6c1d38a..8d591fa 100644
--- a/CMLibSanitizers.cmake
+++ b/CMLibSanitizers.cmake
@@ -1,6 +1,6 @@
-if(DIRECTORY CMLIB_MODULE_DIR)
+if(IS_DIRECTORY "${CMLIB_MODULE_DIR}")
   set(CMLIB_SANITIZERS_DIR "${CMLIB_MODULE_DIR}/thirdparty/sanitizers/cmake")
-  if(DIRECTORY CMLIB_SANITIZERS_DIR)
+  if(IS_DIRECTORY "${CMLIB_SANITIZERS_DIR}")
     list(APPEND CMAKE_MODULE_PATH ${CMLIB_SANITIZERS_DIR})
   else()
     message(WARNING "Sanitizers submodule not found.")